TAOISEACH Leo Varadkar has called on the British government to do the "honourable" thing and hold a public inquiry into the loyalist murder of solicitor Pat Finucane.
He was speaking after the Supreme Court in London ruled a high-profile review into his death did not meet human rights obligations.
Mr Finucane (39) was gunned down in front of his family by a UDA murder squad, which included British state agents, in February 1989.
His family has fought a lengthy legal battle for a public inquiry, a campaign which culminated in yesterday's Supreme Court ruling.
In 2011 former British Prime Minister David Cameron rejected calls for an inquiry and instead ordered Sir Desmond de Silva QC to carry out a review.
He found "shocking" levels of state collusion involving the British army, police and MI5 but ruled out an "overarching state conspiracy".
Mr Finucane's widow Geraldine later described the 2012 report as a "whitewash".
The Supreme Court has now ruled that the de Silva review was not compliant with Article 2 of the European Convention on Human Rights, which required the investigation to be provided with "the means where, if they can be, suspects are identified and, if possible, brought to account".
Lord Kerr, who delivered the judgment, declared that there has not been an effective investigation into Mr Finucane's murder, but added: "It does not follow that a public inquiry of the type which (Mrs Finucane) seeks must be ordered."
Speaking in the Dail yesterday Mr Varadkar said: "The position of the Irish government is that the British government should now honour its commitment to now carry out a public inquiry in accordance with the inquiries act, into the murder of Pat Finucane."
He said the British government should keep a promise made by former Prime Minister Tony Blair at Weston Park in 2001 and accept the judgment made by the Supreme Court.
"It is the honourable thing to do, the right thing to do, and I believe the British government should do that," he said.
"I will certainly be raising it in my meetings with the prime minister. I will be pressing my counterpart Theresa May to honour the commitment made by her forebear."
A spokesman for Mrs May said: "We recognise the suffering of Mrs Finucane caused by the appalling murder of her husband.
"In 2012, the then prime minister apologised for the collusion which took place and which should never have happened."
The spokesman said they are considering the judgment.
He added that the judgment "makes it clear that it is for the state to decide what form of investigation, if indeed any is now feasible, is required in order to meet the investigative requirements".
Geraldine Finucane last night claimed the judgment was a "historic moment" and repeated the call for a public inquiry.
"I stand before you today outside the United Kingdom Supreme Court with one simple message `we have won'," she said.
"My family and I have endured three private police investigations, two confidential documentary reviews, secret government negotiations and a long and difficult court case. We have had to overcome obstacles the likes of which no other family has faced."
SDLP policing and justice spokeswoman Dolores Kelly, who backed a public inquiry, said: "Many families, like the Finucanes, who lost loved ones as a result of state collusion have been shamefully denied the truth for too long."
Sinn Féin president Mary Lou McDonald also urged a public inquiry.
"The withholding of information on the part of the British government and the disregard shown to victims in the courts is a feature of many other cases also - this must stop," she said.
DUP MP Jeffrey Donaldson last night said: “We need to see a comprehensive and proportionate approach to dealing with the past."
